In general, an LCD (Liquid Crystal Display) has been extensively used because it can be made lightweight and thin and its consumption power can be reduced. The LCD displays an image by using properties of liquid crystal that the alignment of molecules is changed according to the voltage or temperature. The LCD includes a BLU (Back Light Unit) and an LCD panel. The BLU is installed on a back surface of the LCD panel to irradiate light to the LCD panel. The LCD panel displays a picture by using the light incident from the BLU.
The BLU includes a light source for generating light and is classified into a direct type BLU and an edge type BLU according to the position of a light source. In the edge type BLU, the light source is placed at a side the BLU, and the light generated from the light source is guided through a light guide plate such that the light irradiates to the LCD panel. In the direct type BLU, the light source is located corresponding to the back surface of the LCD panel, such that the light generated from the light source irradiates directly to the LCD panel.
However, the BLU described above has a problem in that light irradiates non-uniformly to the LCD panel. For this reason, a performance of an LCD may deteriorate. Thus, in order to solve the problem, a distance between the direct type BLU and the LCD panel must be ensured. As the distance between the direct type BLU and the LCD panel becomes widened, the performance of the LCD may be more improved.
However, the thickness of the LCD may become large proportionally to the distance between the BLU and the LCD panel. That is, it is difficult to make the LCD small. Thus, there is a need to provide a method for ensuring brightness uniformity while making the LCD in a small size.